It is well known that watercraft are typically powered by outboard motors that drive a propulsion device which in turn propel a watercraft through the water. These outboard motors are typically powered by an engine of the internal combustion variety. The engine includes an air intake which communicates with each combustion chamber of the engine.
It is common to position a throttle plate within the air intake. The throttle plate is typically arranged to move between open and closed positions, thereby altering the cross-sectional area of a passage through the air intake. This in turn changes the volume of air which is permitted to flow through the air intake to the combustion chamber(s) of the engine.
Also well known in the art is that the position of the throttle plate is controlled, either directly or through an engine control module, by an operation device located on the motor, or more preferably, the watercraft. Such an operation device may comprise a combined throttle and transmission control for the watercraft. Typically, the position of the operation device correlates to a certain opening position of the throttle plate. At each position of the operation device, the throttle plate is thus at a certain position allowing a given amount of air is allowed to flow through the engine, which in turn allows the engine to operate at a given engine speed.
There are certain operating conditions, however, where the throttle position set by the position of the operation device will not produce the desired engine speed for the load placed upon the engine. For instance, when the operation device is positioned in a forward position the engine typically is operating under a given speed and there is a set amount of torque on the propulsion device. When the operation device is moved from a mode of operation in the forward position to a mode of operation in the reverse position, the position of the throttle plate will not correlate to the load on the engine caused by the propulsion device.
A more specific example is when the operator of the watercraft uses the motor to slow the watercraft. The operation device is positioned in a forward position and then the operator shifts the operation device to the rearward position or to a neutral position. In this case, the throttle plate may be positioned so that the air intake member is completely closed. The load on the engine, however, does not correlate with the position of the throttle plate and subsequently the engine may bog down or even stall entirely.
Another situation where the load on the engine will not correlate with the position of the throttle plate is when the operation device is moved from a rearward to a forward position. In this position, the throttle plate position will not correlate with the load placed on the engine and therefore the engine may subsequently bog down or even stall.
Yet another situation where the load on the engine will not correlate with the position of the throttle plate as set by the operation device is when the operator shifts either from a forward position to a reverse position at a high rate of speed. Once again, the engine may be overloaded and may bog down or stall.
Still another situation where the load on the engine will not correlate with the position of the throttle plate as set by the operation device is when the watercraft is in a trolling mode and the operator suddenly shifts either from forward to reverse or from reverse to forward. As before, the engine may be overloaded and may bog down or stall.
It is therefore a present object of the invention to prevent the bogging down or stalling of the engine of the watercraft under all of the situations of operation as listed above.